Method of manufacturing laminated wafer by high temperature laminating method

Abstract

To provide a method of manufacturing a laminated wafer by which a strong coupling is achieved between wafers made of different materials having a large difference in thermal expansion coefficient without lowering a maximum heat treatment temperature as well as in which cracks or chips of the wafer does not occur. A method of manufacturing a laminated wafer 7 by forming a silicon film layer on a surface 4 of an insulating substrate 3 comprising the steps in the following order of: applying a surface activation treatment to both a surface 2 of a silicon wafer 1 or a silicon wafer 1 to which an oxide film is layered and a surface 4 of the insulating substrate 3 followed by laminating in an atmosphere of temperature exceeding 50° C. and lower than 300° C., applying a heat treatment to a laminated wafer 5 at a temperature of 200° C. to 350° C., and thinning the silicon wafer 1 by a combination of grinding, etching and polishing to form a silicon film layer.

What is claimed is: 
     
       1. A method of manufacturing a laminated wafer by forming a silicon film layer on a surface of an insulating sapphire wafer, quartz wafer or alumina wafer substrate, the method comprising the steps in the following order of:
 applying a surface activation treatment to a surface of a silicon wafer or to a surface of a silicon wafer covered with an oxide film, and to the surface of the insulating sapphire wafer, quartz wafer or alumina wafer substrate; 
 bonding the surfaces to each other in an atmosphere of temperature exceeding 50° C. and lower than 300° C.; 
 subjecting the bonded substrates to a heat treatment of 200° C. to 350° C. wherein the temperature for subjecting the bonded surfaces to a heat treatment is higher than the temperature for bonding the surfaces to each other by 50° C. to 150° C.; and 
 thinning the silicon wafer by a combination of grinding, etching and polishing to form the silicon film layer on the insulating sapphire wafer, quartz wafer or alumina wafer substrate. 
 
     
     
       2. The method of manufacturing a laminated wafer according to  claim 1 , wherein the surface activation treatment is any one of an ozone water treatment, a UV ozone treatment, ion-beam treatment and plasma treatment, or any combination thereof. 
     
     
       3. The method of manufacturing a laminated wafer according to  claim 1 , wherein the step of bonding comprises heating, with hot plate apparatus, both of said surface of the insulating substrate and said surface of the silicon wafer or heating only said surface of the insulating substrate. 
     
     
       4. The method of manufacturing a laminated wafer according to  claim 1 , wherein an etching solution used in the step of thinning comprises a solution of one or more alkalis selected from a group consisting of KOH, NH 3 , NaOH, CsOH and NH 4 OH. 
     
     
       5. The method of manufacturing a laminated wafer according to  claim 1 , wherein an etching solution used in the step of thinning comprises at least one organic solvent selected from a group consisting of ethylenediamine pyrocatechol water, tetramethylammonium hydroxide, and hydrazine. 
     
     
       6. The method of manufacturing a laminated wafer according to  claim 1 , wherein a dose amount of hydrogen ions (H + ) implanted to the silicon wafer is from 3.0×10 16 /cm 2  to 1.0×10 17 /cm 2  or a dose amount of hydrogen molecule ions (H 2   + ) implanted to the silicon wafer is from 1.5×10 16 /cm 2  to 5.0×10 16 /cm 2 . 
     
     
       7. The method of manufacturing a laminated wafer according to  claim 1 , wherein the root-mean-square roughness of the surface of the silicon wafer and/or the surface of the insulating substrate before the surfaces are bonded is not more than 0.5 nm. 
     
     
       8. A wafer obtained by the method of manufacturing a laminated wafer according to  claim 1 .